Providing high quality, evidence-ba...

Providing high quality, evidence-based care to our clients requires critical review of the literature. Part I: Applied Statistics describes the basic principles of applied statistics for evaluating the statistical and clinical quality of the literature. Different research designs are used depending upon the hypothesis to be exhibitioned and resources available; some designs are more powerful in deriving significant conclusions further also have limitations. Statistical significance, determined mathematically, is essential still not synonymous to clinical importance. Determination of clinical importance will vary depending forward the outcome measure and its specific words immediately preceding [i]or[/i] following By applying some of the basic principles outlined in this paper, the clinician can better assess the merit of the methodology, data analysis, and ensues reported in research papers. In addition, this paper provides background information for Part II: Grading the Evidence.

Key Words: professional practice, evidence based, studious mood design, clinical research, clinical trials

INTRODUCTION

We are all faced with the influences of providing high quality care that is evidence based however how do we sort by the agency of and integrate information from various reports forward cardiopulmonary physical therapy? Further, in what way do we determine what treatment to perform if 2 studies forward the same physical therapy intervention contradict each other? Lastly, to what degree do we find time to read and synthesize the information from the mountain of journal articles related to our particular area of practice?... or do we simply confidence that one day the stack of unread journals will topple through and inadvertently fall into the waste paper bin?

This paper will describe fundamental principles of evaluating the statistical and clinical quality of research studies by way of describing basic research designs, statistical significance, clinical importance, and grading of clinical trials. Part of this article inevitably involves technical and methodological terms; however, clinical examples related to cardiopulmonary physical therapy are many times used to illustrate examples and clinical relevance.

RESEARCH DESIGN

During our search for knowledge, we are expos to a variety of research studies based forward different research designs. Each research design has its benefits and shortcomings.' The main characteristics of more [i]or[/i] less of the common designs used in physical therapy studies are listed in Table 1

Randomized rule trials (RCTs) are considered to be the gold standard for clinical trials.' Their main features are outlined in Table 1 the same of the strongest features of a RCT is the inclusion of a placebo or untreated curb group, however, some describe this to be in violation of article 113 of the Declaration of Helsinki.' It states that "in any medical close attention every patient-including those of a curb group, if any-should be assured of the best proven diagnostic and therapeutic method" However, in at hand times, evidence from RCTs is many times required before a treatment can be approved on third-party payers. Temple et a 16 argued that article 113 is untenable. Instead placebo-controlled trials can ethically be carried disclosed so long as the make submissives are not harmed by deferral of therapy.' Begg et ale propos standards and methodology in reporting RCT The checklist contains 21 items that are related to the methodology, ensues discussion, and other essential items in the same state [i]or[/i] condition as those that can be used to assess the internal (Internal validity is described as being healthy when manipulation of the independent variable is the sole factor producing changes in the contingent variable. In other words, extraneous factors that can affect the pendent variable are well controlled) and external validity (External validity pertains to the ability to generalize or apply the conclusions to a larger population than the sample of folks examined in the study.) of the trial.

The case-control design examines the efficiency of an intervention on a assemblage of patients and a assign places to of healthy subjects that are matched in several characteristics leaving out for the presence of the disease or condition. This protoplast of design is viewed to have les potential harm to the research patients. The shortcoming of this prototype of design, however, is that mild cases are usually omitted from the case selection, leading to exaggerated or inflated treatment effects9

A pre-post or repeated measure design uses data from pre-treatment phase as the have charge of data to compare to the post-treatment data in order to discern if a treatment import has occurred. The pre-post design is often used in physical therapy studies. Table 2 indicates the advantage of the pre-post design compared to the RCT in denominations of the sample size required; the pre-post design requires just above half as many patients as the RCT design. From a practical perspective, this is a major advantage since recruitment of patients with appropriate research inclusion characteristics is often the most numerous difficult feature of carrying on the outside clinical trials. The shortcoming of the pre-post design is that it can overestimate a positive treatment force relative to the RCT design."